It was no accident that Seattle drivers woke up Friday morning to bare arterial streets, including a nearly slush-free Aurora Bridge.

The 167-foot high span was street maintenance director Steve Pratt’s main worry overnight — because the air was still freezing, and cooled the steel bridge from beneath. In addition to that crossing, he put extra emphasis on clearing snow-covered Martin Luther King Jr. Way South, along with 15th Avenue Northwest and 15th Avenue Northeast, among others. The West Seattle Bridge route and Alaskan Way Viaduct already were in great shape and stayed that way.

As the melt begins Friday, many streets and sidewalks are still icy. If a road isn’t on a transit route, it generally wasn’t plowed or salted. A clear example is around Greenlake, where Winona Avenue North and West Greenlake Avenue North are still packed ice while North 80th Street is down to only a little slush.

Because the chill persisted an extra day and a half longer than forecast, the city spent another $150,000 to $200,000 for its clearing work, plus $15,000 to $20,000 for extra help, on top of the $500,000 or so for the initial snow response, Pratt said in an interview Thursday evening.

At 2 p.m. Thursday, Pratt called on MidMountain Contractors of Kirkland, a frequent builder of major road projects in Seattle, to dispatch three road graders to add to the city’s own fleet of 30 vehicles. Two of them in tandem cleared Fairview Avenue North. Pratt planned to call MidMountain earlier if Seattle got the 15 inches of snow originally forecast, but only six inches fell, so he delayed doing so until freezing rain showed up Thursday.

Pratt said that generally, the city clearing efforts went well, given the changing conditions. Boren Avenue near the hospitals was de-iced and easily drivable as early as Wednesday night.

It appears the only noteworthy lapse was Wednesday morning, when transit buses had to creep down an unplowed hill on Third Avenue year Yesler Way — causing delays that spread to outlying areas — before city plows reached that block about 10 a.m.

Seattle applied so much salt that stockpiles nearly ran out at all three maintenance yards, and the city called public utilities truck drivers to fetch more from a vendor near the Duwamish River. The vendor was unable to deliver the pinkish Canadian salt fast enough to both Washington state DOT and Seattle, said Pratt.

Mayor Mike McGinn, whose win came in part because of his predecessor fumbling a 2008 ice storm, has boosted the winter road-response budget, to $1.14 million for 2012. Pratt said this week’s truckers are restocking the depleted salt piles, of some 2,000 tons, to be ready for the next snow event.